Protection device for an encoder in a rolling bearing

Abstract

 Protection device (1) for an encoder (2) in a rolling bearing (3) which is axially blocked by a shoulder (7), the device (1) presenting a support shield (8) for the encoder (2) which is force fit onto an inner race (5) of the bearing (3), and two sealing covers which are mounted, a first shield (12) which is mounted in such a way as to protect the encoder (2), and a second shield (13) which is mounted between an axially blocking rolled border (6) of an inner race (5) of the bearing (3) and the shoulder (7) ; a connecting bellows element (14) being interposed between the two covers (12, 13) in order to connect the two covers themselves (12, 13) to each other, in such a way as to define a single sealing body which is made of rubber material.

Description

[0001] The present invention relates to a protection device for an encoder in a rolling bearing.

[0002] In general, the device according to the present invention may be advantageously applied in the field of rolling bearings for wheel hubs, in which an inner race of the bearing is axially blocked by the wheel hub by means of a rolled border on the inner race itself, and in which the wheel hub is mounted with the rolled border in such a way that it abuts a shoulder of a blocking joint of the bearing itself.

[0003] In the above-described field, well-known protection devices for encoders comprise a support shield which is integral with the encoder and which is force fit onto the inner race, and two annular sealing covers which are independent from each other, a first cover of which is mounted onto an outer race of the bearing in a frontal position to the encoder, and presents a rigid shield which is internally lined with rubber material, while a second shield is snap fitted onto the rolled border and presents a dynamic sealing element which is in sliding contact with the first cover, and a distance ring which is made of plastic material and which is interposed between the rolled border and the shoulder.

[0004] Furthermore, the first sealing cover presents at least one window which is obtained through the rigid shield in order to permit a reading sensor to face the encoder, the reading sensor being however separated from the encoder itself by an elastic wall which is defined by the internal lining material.

[0005] Although the above-described kind of protection devices have been shown to be very functional for some kinds of applications, they have however been shown to have some disadvantages in other applications, such disadvantages being related to the adoption of two covers which are independent from each other, and to the impossibility of protecting the encoder in a more direct manner. The adoption of two covers involves an assembly operation for each cover in a fashion that is substantially separate from the other cover with the use of some caution in the positioning of the sealing element which is interposed between the two covers, as well as the substantial difficulty of protecting the encoder more closely and directly in spite of the fact that current allowances and methodology relating to working and assembly lead to extremely positive results nowadays.

[0006] The aim of the present invention is to produce a protection device for an encoder in a rolling bearing, which will be absent of the above-described disadvantages.

[0007] According to the present invention, a protection device for an encoder in a rolling bearing will be produced, which is axially blocked by a rolled border on a respective inner race, and is mounted in such a way that the rolled border abuts a blocking shoulder; the device comprising a support shield which is integral with the encoder and which is mounted onto the inner race, a first sealing cover which is mounted in a position which is frontal to the encoder, and a second sealing cover which is interposed between the rolled border and the shoulder; the device being characterised by the fact that it comprises connecting means between the said first and second covers and defines a single body with the first and second covers themselves.

[0008] The present invention will now be described with reference to the attached drawings, which illustrate a non-limiting form of embodiment of the present invention, and in which:

• FIGURE 1 illustrates, in axial section, a first preferred form of embodiment of a protection device for an encoder in a rolling bearing according to the present invention; and
• FIGURES 2, 3, and 4 illustrate respective further alternative forms of embodiment of the protection device shown in FIGURE 1.

[0009] With reference to FIGURE 1, the number 1 indicates a protection device for an encoder 2 in a rolling bearing 3 in its entirety.

[0010] The bearing 3 comprises an outer race 4 and an inner race 5 which is rotatable around a rotation axis (which is noted, but not illustrated, and which is indicated in the following, for greater clarity, with the letter A), and is axially blocked by a border 6, which is rolled onto the race 5 itself, and which is mounted in such a way as to abut a blocking shoulder 7 of the bearing 3, or rather with its own frontal surface 6s, which is transverse to the axis A, facing and parallel to a frontal surface 7s of the shoulder 7.

[0011] The device 1 comprises a metallic support shield 8, which presents a flange 9 which is integral with the encoder 2, and a cylindrical wall 10 which is transverse to the flange 9 and which is force fit onto the inner race 5. In particular, the cylindrical wall 10 is defined by two cylindrical portions 10a and 10b which are folded one on the other, and of which the portion 10a is connected to the flange 9, while the portion 10b is arranged internally to the portion 10a, and is directly force fit onto the inner race 5. Furthermore, the portion 10b presents an annular frontal surface 10s which is axially arranged in alignment to a frontal surface 5s of the inner race 5, and the flange 9 presents a border 11 which is axially turned towards the outside of the bearing 3 and on the outer periphery of the encoder 2 in such a way as to radially block the encoder 2 itself.

[0012] Finally, the device 1 comprises a sealing cover 12 which is mounted in a position which is frontal to the encoder 2 and the inner race 5, a sealing cover 13 which is interposed between the border 6 and the shoulder 7, and a connecting bellows wall 14 between the covers 12 and 13 themselves. In particular, the covers 12 and 13 and the bellows wall 14 are made of rubber material which is defined by elastomeric rubber and they define a single body which is integral with both the shield 8 and the encoder 2 and which is suitable both for protecting the encoder 2 itself, and for crating a static seal between the border 6 and the inner race 5, as well as a dynamic seal between the device 1 and the outer race 4.

[0013] The cover 12 comprises a protection wall 15 which is closely connected with the encoder 2 and with the shield 8, and is arranged in contact with the surface 5s of the inner race 5, and a sealing element 16 which is defined by a shaped lip which extends from the protection wall 15 towards the outer race 4 of the bearing 3 in order to create a labyrinth seal with the outer race 4 itself.

[0014] The wall 15 presents an external peripheral border 17 which is of a substantially cylindrical shape and which is connected to the border 1 of the flange 9, and an internal peripheral border 18, which is connected to the bellows wall 14, and which is arranged in such a way as to abut the surface 5s. Furthermore, the wall 15 presents a frontal relief 19 which is arranged in correspondence with the support surface 10s in order to permit an assembly thrust of the device 1 itself onto the bearing 3, avoiding, furthermore, that the allowances which have a bearing on the axial position create deformations in the reading zone of the encoder 2. The wall 15 entirely covers the portion 10b in correspondence to the surface 10s thus completely covering, and at least from the external part of the bearing 3, the encoder 2 and protecting the encoder 2 itself from any eventual impacts, damage during manipulation, stones or other contaminating agents. Furthermore, considering that the encoder 2 is at this point arranged inside a sealed chamber 20 and defined on one side by the shield 8 and on the other side by the wall 15, and furthermore considering the elasticity of the material which defines the wall 15 itself, it is possible to guarantee the encoder 2 itself with greater thermal deformation, and it is also possible to avoid even considerable damage to the encoder 2 in the case in which a reading sensor 21 comes into contact with the encoder 2.

[0015] The cover 13 comprises an annular sealing wall 22 which is blocked between the surface 6s of the border 6 and the surface 7s of the shoulder 7 in order to create a damping effect between the shoulder 7 which axially blocks the bearing 3 and the border 6 themselves in such a way as to eliminate the noise which is created under tangential accelerating conditions. The annular wall 22 also functions as a static seal between the border 6 and the shoulder 7, thus avoiding any potential corrosion of the area between the border 6 and the inner race 4 which is to the advantage of improving the resistance of the blocking of the bearing 3.

[0016] The annular wall 22 is also radially delimited towards the inside by a cylindrical surface 23, and is radially delimited towards the outside by an external peripheral border 24, which is radially curved towards the inside and axially towards the bearing 3, and is connected to the bellows wall 14.

[0017] The bellows wall 14 is connected in correspondence to its own axially opposite ends to the border 18 and the border 24, and is axially deformable due to both the elasticity of the rubber material from which it is made, and due to its own conformation which permits a dimensional variation in an axial direction that allows it to conform to dimensional variations in the border 6 or to any stress to which it might be subjected during use.

[0018] The bellows wall 14 comprises a tapering portion 25 which is open towards the inside of the bearing 3, and two shaped portions 26 and 27 which are arranged between the tapering portion 25 and, respectively, the border 18 and the border 24, and of which the shaped portion 26 presents a substantially cylindrical conformation, while the portion 27 presents in turn a tapering conformation, but open towards the outside of the bearing 3.

[0019] The forms of embodiment which are illustrated in FIGURES 2, 3 and 4 relate to respective devices 1', 1", and 1"' which are similar to the device 1, from which each of these devices differs due to a respective element of construction.

[0020] In particular, and in accordance with what is better illustrated in FIGURE 2, the device 1' differs from the device 1 due to the fact that the portion 10b of the cylindrical wall 10 is replaced with an internal lining layer 31, which is made of rubber material and is an integral part of the cover 12, and is thus interposed between the portion 10a of the wall 10 and the inner race 5.

[0021] The layer 31 presents a ragged internal cylindrical surface 31s which is suitable for increasing the friction between the shield 8 and the inner race 5 in order to ensure a radial and axial blocking of the device inside the bearing 3.

[0022] Instead, in accordance with what is better illustrated in FIGURE 3, the device 1'' differs from the device 1 due to the fact that the shield 8 comprises an axial blocking element 41, which is integral with the portion 10b of the wall 10, and is arranged in such a way as to abut the surface 5s of the inner race 5. In particular the element 41 replaces the surface 10s, and is folded at an angle of 90° in relation to the portion 10b in an internally radial direction, and is completely covered by the border 18 which has an axial thickness which is greater than that in the case of the device 1.

[0023] Finally, and in accordance with what is better illustrated in FIGURE 4, the device 1"' instead differs from the device 1 due to the fact that the border 11 is replaced by a border 11"' which is axially turned towards the inside of the bearing 3 and does not cover the outside of the encoder 2, and the sealing element 16 is defined by a contacting lip which radially extends towards the outside of the border 11. In this case, furthermore, the border 17 of the wall 15 completely covers the external edge of the encoder 2 as well as the external edge of the border 11'''.

[0024] Any of the above-described devices 1, 1', 1", and 1''' whatsoever may be completed with the addition of a further shield 50, which is axially arranged inside the shield 8, and which is force fit inside the race 4, and is provided with a respective contacting lip 51 which is arranged in sliding contact with the portion 10a and the flange 9 of the shield 8 itself.

[0025] It is intended that the present invention should not be limited to the forms of embodiment herein described and illustrated, which are to be considered as examples of forms of embodiment of a protection device for an encoder in a rolling bearing, and which might be subject to further modifications relating to the shape and disposition of the parts and to details pertaining to construction and assembly.

Claims

1. Protection device (1) (1') (1") (1'") for an encoder (2) in a rolling bearing (3), which is axially blocked by a rolled border (6) on a respective inner race (5), and is mounted in such a way that the rolled border (6) abuts a blocking shoulder (7); the device (1) (1') (1") (1"') comprising a support shield (8) which is integral with the encoder (2) and which is mounted onto the inner race (5), a first sealing cover (12) which is mounted in a position which is frontal to the encoder (2), and a second sealing cover (13) which is interposed between the rolled border (6) and the shoulder (7); the device (1) (1') (1") (1''') being characterised by the fact that it comprises connecting means (14) between the said first and second covers (12, 13) and defines a single body with the first and second covers (12, 13) themselves.

2. Device according to Claim 1, characterised by the fact that the first cover (12) is made of rubber material, and comprises:

- a protection wall (15) which is closely connected with the said encoder (2) and which is arranged partially in contact with the said support shield (8); and

- a sealing element (16) which substantially extends from the protection wall (15) towards an outer race (4) of the said bearing (3).

3. Device according to Claim 2, characterised by the fact that the second cover (13) is made of rubber material, and comprises an annular sealing wall (22) which is blocked between the rolled border (6) and the shoulder (7), both for creating a damping effect between the rolled border (6) and the shoulder (7) themselves, and for creating a static seal on the rolled border (6).

4. Device according to Claim 3, characterised by the fact that the said connecting means (14) are made of rubber material, and are axially deformable.

5. Device according to Claim 4, characterised by the fact that the said connecting means (14) comprise a bellows wall (14) which is integral with both the protection wall (15) of the first cover (12) and the annular sealing wall (22) of the second cover (13).

6. Device according to Claim 5, characterised by the fact that the said rubber material is defined by elastomeric rubber.

7. Device according to any of the Claims from 2 to 6, characterised by the fact that the support shield (8) comprises a support flange (9) which is directly connected to the encoder (2) and a cylindrical wall (10) which is made of metallic material and which functions to anchor the encoder (2) to the inner race (5).

8. Device according to Claim 7, characterised by the fact that the cylindrical wall (10) is directly force fit onto the inner race (5) itself.

9. Device according to Claims 7 or 8, characterised by the fact that the support shield (8) comprises an axial blocking element (41), which is integral with the cylindrical wall (10), and which is arranged in such a way as to abut an external axial surface (5s) of the inner race (5).

10. Device according to Claims 7, 8, or 9, characterised by the fact that the support shield (8) comprises a lining (31) which is made of rubber material and which is integral with the said cylindrical wall (10) and which is interposed between the cylindrical wall (10) itself and the said inner race (5).

11. Device according to Claim 10, characterised by the fact that the said lining (31) which is made of rubber material is an integral part of the said first cover (12) and presents an internal ragged cylindrical surface (31s) which functions to increase the adherence between the support shield 88) and the inner race (5).

12. Device according to Claim 7, characterised by the fact that the said sealing element (16) is integral with the protection wall (15) and comprises a shaped lip (16) which is arranged to face the outer race (4) in order to create a labyrinth seal.

13. Device according to Claim 7, characterised by the fact that the said sealing element (16) comprises a contacting lip (16) which radially extends towards the outside of the said support shield (8); the said support flange (9) presenting an external radial border (11) which is turned towards the interior of the bearing 3 in support of the contacting lip (16).

14. Device according to any of the preceding Claims, characterised by the fact that the first cover (12) comprises a frontal relief (19) which is arranged in correspondence with the support shield (8) in order to provide an assembly thrust of the device itself in relation to the bearing (3).

Drawing